Gas shielded metal arc welding torch



Feb 10, 1959 P. R. scHAEl-R ETAL 2,873,355

GAS SHIELDED METAL ARC WELDING TORCH Filed April 5, 1957 PETER R.SCHAEFER THADDEUS J. WOJCIAK v STANLEY H. ROYER aA//JJ ATTORNEY.

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oas snrarnnn METAL ARC WELDING 'rouenl Peter R. Schaefer, Newark, andThaddeus l. Wojciak and Stanley H. Royer, Elizabeth, N. J., assignors toglnn Carbide Corporation, a corporation of New or This invention relatesto gas shielded metal arc welding torches, and moreparticularly to ahand gun for feeding very small electrode wire. l

Torches of this character are provided with a guide tube for directingthe electrode wire out through the discharge orifice, and for supplyingelectric welding current to the electrode wire passing therethrough.Momentary loss of contact in the guide tube caused currentA surges andburnback requiring replacement of the guide tube. This guide tubereplacement vin former torches has 'been a cause of much vdown time inthe welding operation.

The main objects of the present invention are to eliminate thedifficulties referred to above, to smooth out current surges and therebystabilize the arc, to reduce the down time previously required forreplacement of damaged guide tubes, and to provide a more compact pulltype sigma gun.

' According to the present invention the loss of contact is prevented byfeed back of the welding current to the wire driving rolls, preferablyby a brush engaging a co1- lector ring for one of the feed rolls. Theremoval of the guide tube is facilitated by a collet control memberrotatably mounted between the gun barrel and nozzle, and means actuatedby turning the control member in opposite directions for causingrelative longitudinal movement of the collet body and collet torespectively grip and release the guide tube.

In the drawings:

Fig. 1 is a horizontal section through a hand gun according to thepreferred embodiment of the present invention;

Fig. 2 is a section taken along the line 2-2 of Fig. l; and

Fig. 3 is a section taken along the line 3--3 ofFig. l.

The torch shown in the drawing comprises a portable hand gun providedwith a drive unit assembly or handle 1G having a barrel 12, a motorsupport portion 14 and a hand grip portion 15. The barrel 12 contains anelectrode wire guide tube 16. A gas directing nozzle 18 surrounds theouter end of the guide tube 16 and extends therebeyond to a dischargeorifice 20.

For securing the guide tube 16 in the barrel 12, a collet body 22 isslidably mounted in the bore thereof, and a collet 24 is slidable in thebore of the collet body. For securing the nozzle 18 to the barrel 12,the nozzle is screwed into a water jacket 26 bolted to the plasticinsulator body 28. A locking nut 30 is screwed onto the body 28, andcontains a spring tempered locking ring 32 having ngers 34 extendingthrough slots in the body 28 and contacting an annular lip 36 on thecollet body 22. When the locking nut 30 is tightened onto the insulatorbody 28, the force exerted on the spring tempered locking ring 32 istransmitted to the collet body 22, moving it back into the torch so asto load the conical seat on the collet. Therefore, quick release of thetorch guide tube is accomplished by merely loosening the locking nut.

Driven feed roll 38 and driven back-up roll 40 are journaled in asection V3 9 vof the drive unit assembly 10 Patent Oi 2,873,355 PatentedFeb. 10, 1959 2 behind the guide tube 16 for pushing the electrode wire25 through the guide tube and on out through the discharge orifice 20.For driving these rolls, a gear box 42 and a wire feed motor 48 aremounted in the rear portion of the drive unit assembly 10. The feedmotor is energized from a lighting circuit source, and is provided withan inching button 49 on the handle 15. Guide tube replacement isaccomplished by inching out the wire guide tube by means of the wireinching button 49 after the locking nut has been loosened. This easyguide tube replacement is accomplished without having welding current onthe wire, and without interfering with the feed roll section of thetorch, and no tools are required.

The electrode wire 25 is supplied from a reel 50 through a flexibleconduit 52 to the rear of the drive unit assembly 10. The wire feedmotor 48 has a hollow armature l54 journaled in bearing bells 55 and 56in the drive unit assembly 10. The hollow armature 54 has an extensioninto the gear box 42 forming a hollow shaft for a worm 58 driving a wormgear 60. The electrode wire 2S rfrom the conduit passes through thehollow armature 54 and hollow Worm shaft to the feed roll 38 and backuproll 40. The worm gear 60 is rigid with the shaft of a pinion 62 meshingwith a gear 64 rigid with the shaft of the driven feed roll 38. Piniongear 77 rigid with the shaft of driven feed roll 38 meshes with matingpinion gear 78 rigid with the shaft of driven back-up roll i 40 to drivethe back-up roll.

Shielding gas such as argon is supplied from a hose 67 entering the rearof the motor support section 14 and connected to the rear of the barrel12 by a tube 66. Electric welding current is supplied by a conductor 68in a water outlet hose 69 entering the rear of the motor support section14, which hose is connected to the barrel 12 by a tube similar to tube66. A trigger switch 65 on the hand grip portion 15 energizes thewelding circuit through a relay in the control apparatus. The weldingcurrent passes through barrel 12, collet 24, and guide tube 16 to theelectrode wire 25.

Feed back of the welding current for the hot feed roll operation issupplied by another conductor 72 from the barrel 12 to a spring brush 74engaging a collector ring 76 on the shaft of the driven feed roll 38.

What is claimed is:

l. In an inert gas shielded metal are welding gun comprising a barrel,an electrode wire guide tube in said barrel, a gas directing nozzlesurrounding the outer end of said guide tube and extending therebeyondto a discharge orifice, feed rolls journaled in said gun behind saidguide tube for pushing the electrode wire through said guide tube and onout through said discharge orifice, means for supplying electric weldingcurrent through said barrel to said guide tube, a collector ring on oneof said feed rolls, and a brush for supplying welding current throughsaid brush and collector ring to said feed roll to energize said wireelectrode before it reaches said guide tube.

2. in an inert .gas shielded metal arc welding gun comprising a barrel,a collet in said barrel, an electrode Wire guide tube gripped by saidcollet, a gas directing nozzle surrounding the outer end of said guidetube and extending therebeyond, and means actuated from the dischargeend of said gun without removing said nozzle for releasing said collet.

3. In an inert gas shielded metal arc welding gun cornprising a barrel,a collet in said barrel, an electrode wire guide tube gripped by saidcollet, a gas directing nozzle surrounding the outer end of said guidetube and extending therebeyond to a discharge orifice, feed rollsjournaled in said gun behind said collet for pushing the electrode wirethrough said guide tube and on out through said discharge orifice, meansfor supplying electric weide Y devastata ,f

,a M r ing current to said guide tube, and means for supplying electricwelding current through oneeof said feed rolls to the electrode wire toenergize the same before it reaches said guide tube. Y v A Y 4. In aninert gas. shielded metal arc Welding gun' comprising a barrel, a colletbody in said barrel, a collet in said body, an electrode wire guide tubegripped by said collet, a gas directing nozzle surrounding the outer endof said guide tube and extending therebeyond, a collet control memberrotatably mounted between said nozzle and said barrel coaxial with saidguide tube, Yand means actuated by turning slaidrcontrol member inopposite directions foi-causing relative longitudinal movement of saidcollet and body to respectively grip and release said guide tube.

5. In an inert gas shielded metal arc welding gun comprising a barrel, acollet in said barrel, an electrode Wire guidetubegripped by saidcollet, a water jacket surrounding the outer end of said guide tube, agas directing nozzle mounted on said water jacket, a collet controlmember rotatablyV mounted between said water jacket and said barrel, andmeans actuated by turning said control member for releasing the grip ofsaid collet on said guide tube,

6. an inert gas shielded metal arc welding hand gun comprising a barreland a handle, an electrode Wire guide tube in said barrel, a gasdirecting nozzle surrounding the outer end of said guide tube, yfeedrolls journaledl in said gun behind said guide tube for pushing the wiretherethrough, an electric motor behind said feed rolls for drivingthesame, supply hoses on the rear of said gun for supplying shieldinggas, welding current and cooling water thereto, and switches on saidhandle for controlling the supply of current to said feed roll drivemotor and welding current to one of said feed rolls. i Y l 7.v In auinert gasfshielded: metal arc welding gun, a casing comprising bearingbells for a hollow armature, a gearbox secured tofone of saidbearingbells, a freed roll section'securedto said. gear box, a barrel securedto said feed roll section, an electrodey wire guide tube in said barrel,a gas directing Vnozzle surrounding the outer end of said wire-guidetube, said hollow armature having a worm shaft extension driving gearingin said gear box for driving feed rolls in-said section for pulling theelectrode wire through said hollow armature and worm shaft extension andgear box into said feed roll section and pushing said electrodeWirethrough said barrel and guide tube` and out through said nozzle;

References Cited in the tile of this patent i UNITEDA STATES PATENTS Re.14,927 Sessions July 27, 1920 2,236,707 Darner Apr. 1, 1941 2,299,785'Barrett Oct. 27, 1942 2,510,205.` Baird June 6, 1950 2,572,084 WilsonOct. 23, 1951 2,606,267 McElrath Aug. 5, 1952

